1. Field of the Invention
The present invention relates to a surface protection film peeling method for peeling a surface protection film adhered to the front surface of a wafer. The present invention also relates to a surface protection film peeling device for carrying out this surface protection film peeling method.
2. Description of the Related Art
In the field of manufacturing semiconductors, there is a tendency for large-sized wafers to be used year after year. Further, in order to enhance packing density, the wafer thickness is reduced. In order to reduce wafer thickness, usually, after a surface protection film for protecting a semiconductor element has been adhered to the front surface of a wafer, the back surface is ground.
After back-grinding is complete, as shown in FIG. 9, a dicing tape 3 is adhered to the back surface of the wafer 20, so that the wafer 20 and a ring type mount frame 36 can be integrated with each other into one body.
As shown in FIG. 10, the wafer 20 is supported on a table 131 so that a surface protection film 11 can be placed on the upper side. At this time, between the mount frame 36 and the wafer 20, an adhesive face 3a of the dicing tape 3 is annularly exposed. A peeling tape 4 is drawn out onto a adhering member 146, the cross-section of which is substantially triangular and the adhering member 146 is pressed onto the surface protection film 11, so that the peeling tape 4 can be adhered to the surface protection film 11. Then, the table 131 for supporting the wafer 20 is moved in a horizontal direction, a position, at which the peeling tape 4 is adhered, and functions as a peeling start position. Therefore, the surface protection film 11 can be continuously peeled from the wafer 20 from the peeling start position.
As shown in FIG. 10, a tip portion of the adhering member 146 is positioned obliquely downward with respect to the horizontal face and pressed onto the surface protection film 11. However, when the peeling tape 4 is drawn out, the peeling tape 4, which is located at the tip portion 146a of the adhering member 146, is loosened in such a manner that a loop 4′ is formed by the loosened peeling tape 4. Accordingly, the peeling tape 4 comes into contact with an adhesive face 3a of the dicing tape 3. In this case, the thickness of the wafer 20 and the thickness of the surface protection film 11 are much smaller than the size of the adhering member 146.
Since the adhesive face of the peeling tape 4 is stuck onto the adhesive face of the dicing tape 3 in this case, when these tapes 3, 4 are adhered to each other, it is very difficult for an operator to separate them 3, 4 from each other without causing damage to the wafer 20. In this connection, even in the case where a cross-sectional shape of the adhering member 146 is not triangular, for example, even in the case where a cross-sectional shape of the adhering member 146 is circular, the same problem can occur.
In order to solve the above problems, Japanese Unexamined Patent Publication No. 2003-22986 discloses a peeling device in which a baffle plate coated with a special peeling coating is arranged at substantially the same height and adjacent to a support table. In this peeling device, when the peeling head for holding the peeling tape is moved on a support table, a protective film 11 is peeled from a front surface of a wafer.
In this peeling device, during the peeling operation, the relative movement of the peeling head and support table is stopped and then the support table is lowered and the baffle plate is horizontally moved toward an edge portion of the wafer. Due to the foregoing, in the peeling device described in Japanese Unexamined Patent Publication No. 2003-22986, the adhesive face 3a between the mount frame 36 and the wafer 20 is covered with a baffle plate. Therefore, it is possible to prevent the peeling tape 4 from adhering to the adhesive face 3a of the dicing tape 3. By moving the peeling head relative to the support table once more, the peeling operation can be started again.
However, in the case of the peeling device disclosed in Japanese Unexamined Patent Publication No. 2003-22986, the peeling operation is stopped once to arrange the baffle plate. Accordingly, peeling time is increased as a result of the stoppage of the peeling operation.
Further, in addition to the movement relative to the peeling head and the support table, it is necessary to lower the support table and move the baffle plate in horizontally. Therefore, the structure of the peeling device disclosed in Japanese Unexamined Patent Publication No. 2003-22986 is complicated. When the structure is complicated as described above, there tends to be a failure in the operation and an increase in the cost of the peeling device.
The present invention has been accomplished in view of the above circumstances. It is an object of the present invention to provide a surface protection film peeling method by which a surface protection film can be peeled in a short amount of time while the peeling tape is prevented from adhering to the dicing tape. It is another object of the present invention to provide a surface protection film peeling device for executing this method.